Transient Thermal Behavior and Diabetic Foot (PICOTE)

In our study, the investigators propose to analyze the transient thermal responses taken at the level of the sole of the foot, following the application of a cold stimulus. By combining a spatio-temporal analysis of these temperature fields and a thermal modeling of the heat transfer in the thickness of the foot, the investigators want to highlight differences between healthy feet vs. pathological feet. Therefore, the investigators will determine the transient thermal responses at the level of the sole of the foot and correlate them with the podological grade.

Both plants of the patient's feet will be observed by a thermal camera. Static observations (taking a single image), or dynamic (taking a series of images) of the foot, will be made. In the latter case, the observation will be done after a brisk walk of 6 min. The instruction given to patients will be to go the furthest in 3 min and then come back in 3 min, all while walking. The observation will be made by cameras without contact. These thermal cameras are non-invasive and non-ionizing, there is no risk related to their use. The camera will be placed on a tripod, a few tens of centimeters from the foot, and connected to a laptop (for the images acquisition). A wooden box, painted black, will be placed around both feet to protect the scene from parasitic thermal radiation that can disturb temperature variations. Foam will protect the skin / wood interface. Electric resistances, fixed on the box, will be placed in the field of vision of the thermal camera to guarantee the good treatment of the images. These resistors will never be in contact with the patient. The area filmed by the camera will be limited to the sole arch and, sometimes, the hand of patients to see if a thermal anomaly is also present on this member.

Measurements of the temperature of the plantar arch by thermal imaging. Result analysis regarding podologic grade ( 0-1-2-3)

The classification of foot risk, mentioned in 2007 in the HAS report, is as follows ([HAS 2007]) Diabetic Foot Report http://www.has-sante.fr/portail/upload/docs/application/pdf/_foot_diabetic.pdf, 2007 : Grade 0: absence of sensitive neuropathy Grade 1: isolated sensitive neuropathy Grade 2: sensitive neuropathy associated with arteriopathy of the lower limbs and/or foot deformities Grade 3: history(s) of foot ulceration (grade3a) and/or lower limb amputation (grade 3b)

Inclusion Criteria: Diabetic subjects (type 1 and 2) age above 18 years old able to walk affiliate to insurance regimen Exclusion Criteria: unable to stay motionless pregnancy subjects with feet wound